The development of digital technology has provided electronic access to a vast amount of information. The increased access to information has fueled an increasing desire to quickly obtain and process the information. This desire has, in turn, placed ever increasing demands for faster and higher capacity electronic information processing equipment (computers) and transmission networks and systems linking the processing equipment (i.e., telephone lines, cable television (CATV) systems, local, wide and metropolitan area networks (LAN, WAN, and MAN). In response to these demands, many transmission systems in use today either have been or will be converted from electrical to optical networks. Optical transmission systems provide substantially larger information transmission bandwidths than electrical systems. Optical transmission systems employ optical fiber in the form of fiber optic cables. Since fiber optic cables are subject to accidents and can become degraded in their performance, it has become increasingly important to be able to test both the communication media and systems to assure that faults are rapidly detected, located efficiently, and quickly fixed.
It may be necessary in installing and/or servicing fiber optic networks to be able to measure insertion loss within an optical network. Insertion loss within an optical network should be determined to be within acceptable limits in order to verify proper physical contact between adjoining optical fibers and to maintain the system loss budget. Currently, one specified way of determining insertion loss is with the use of a hand-held optical network test instrument, which measures the insertion loss through a length of optical fiber that may include one or more joining points between adjoining optical fibers. Such optical network test instrument typically includes one or more optical sources. One of concerns for optical sources in network test instruments is performance. Performance issues may include laser stability under various conditions.
To improve loss test accuracy, it is desirable to improve stability of optical sources in optical network test equipment.